A Windows Vista-like sidebar with clock and news

Once again, the proof that KDE software can do at least as much as Windows...

Creating panel

Right-click on the desktop

Click on Add panel

Click on the Toolbox of this panel

Drag and drop the panel to a side of the screen clicking and holding on Screen edge

Configure the height and width as you wish, but keep quite wide to be able to display the widgets in it

Add widgets

Still in the panel click Add widgets

Add the Analog Clock widget and the News or RSSNow widget

Hide the panel

Click on More settings

Click on the Auto-hide option

You're done!

Result

Using Multiple Plasma Themes

The Plasma workspace allows users to create customized themes whose widgets can be themed using multiple themes. For example, it is possible to have the Taskbar be themed using Oxygen, to have the clock be themed using Aya, and much more customization, allowing you to pick the best plasma themes for each object.

Set up "(Customized)" Theme

Here you can choose what theme is used for different objects in the Plasma workspace. Configure them to your pleasure (it often helps to test each individual plasma element by applying the entire theme to your desktop first) and press Apply.

Apply "(Customized)" Theme

At this point, the workspace settings dialog should list a Plasma theme entitled (Customized). This is the theme mashup that you have created. Select it and hit Apply.